The present invention relates generally to a television system which can be used by a viewer so as to zoom on subjects within the field of view of the cameras and increase the magnification of the image being viewed without effective loss of resolution so as to see the magnified image in greater detail than was possible in prior art electronic zoom systems. The system is operable with both optical and infrared type imaging systems and may be employed in not only the standard television viewing situation but also in imaging systems such as FLIR (forward looking infrared radar) used in ground search operations from aircraft.
Electronic zoom systems are old in the art and examples can be found in U.S. patents such as: U.S. Pat. Nos. 2,510,670 issued to B. S. Trot, June 16, 1950; 3,497,614 issued to E. A. Petrocelli et al, Feb. 24, 1970 and 3,654,386 issued to M. Baum, Apr. 4, 1972. The prior art electronic zoom systems have encountered a difficulty when attempts are made to magnify images within the field of view because the number of scan lines is not increased and the loss of resolution which accompanies the magnification produces an image which has no more information than was in the original picture. Therefore, while the picture size may be increased, there is no more detail to be observed and the magnification does not produce the desired benefit. Accordingly, most television systems that require zoom capability utilize a standard optical zoom system on the television vidicon cameras. The optical systems are rather expensive and are, furthermore, under the camera operator's control rather than the viewer's control.